John Conway

Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass–clover leys cut for silage

Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass-clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.

Nitrogen Management for Profitable Farming with Minimal Environmental Impact: The Challenge for Mixed Farms in the Cotswold Hills, England

A detailed nitrogen (N) budget was constructed for a mixed farm in the Cotswold Hills, England, situated on thin, well drained soils prone to leaching. The study covered all stages of the farms seven-year rotation and included the removal of the dairy herd. All inputs and outputs of N were measured or estimated and a balanced budget achieved, but only by including relatively expensive measurements of soluble organic nitrogen (SON) leached. Leaching was the main loss process. Given the nature of the soil and the influence of the weather, it would be difficult to reduce losses without drastic reductions in fertiliser inputs or stocking rates. Nitrogen use efficiency averaged 46%. The mean N surplus declined from 141 kg N ha−1 to 117 kg N ha−1 with the removal of the dairy herd. However, the farm to which the herd moved had an N surplus of 392 kg N ha−1. Simple farm gate N budgets were constructed for neighbouring Cotswold farms to encourage farmers to consider ways to improve N use. Implications for policy to reduce losses of N while maintaining farm profitability are discussed.

The relationship between risk experience and risk response: a study of farmers and climate change

Within the existing literature, the role of experience of risk on attitudinal and behavioural risk response has been relatively neglected. Recent research that draws on the psychological distance of climate change as a concept notes the importance of local, significant experience as a driver for encouraging appropriate response. The experience of flooding was used as the stimulus in this paper, and emphasis placed on whether direct and/or indirect experience of flood risk is associated with different responses to climate change risk. In order to explore the relationship between climate change risk experience and response in the form of on-farm mitigation and adaptation, this paper draws on a case study of farmers in England, many of whom have experienced flooding. Results from a quantitative survey undertaken with 200 farmers in Gloucestershire, England are discussed. Statistical analysis found experience of flooding to be significantly associated with a heightened concern for climate change. Although also finding an association between experience and behavioural response, the sample were most likely to be taking adaptive behaviour as part of normal practice, with factors such as lack of overall concern for climate change risk and absence of information and advice likely to be the main barriers to action. Risk communication needs to further emphasise the connection between climate change and extreme weather events to allow for farmers to perceive climate change as a relevant and locally salient phenomenon, and subsequent tailored information and advice should be offered to clearly illustrate the best means of on-farm response. Where possible, emphasis must be placed on actions that also enable adaptation to other, more immediate risks which farmers in this study more readily exhibited concern for, such as market volatility.

Influences of one-year red clover ley management on subsequent cereal crops

A field experiment of one-year leys was established at Moreton-in-Marsh, Gloucestershire, UK (NGR SP 217 323) with six combinations of red clover, perennial ryegrass and cocksfoot and two fallow control plots in May 2010 to determine the effects of ‘cut and remove’ cropping three times or ‘cut and mulch’ once annually on biomass yield and nitrogen (N) accumulation. The effect of fertility building leys on grain yield and quality were studied in two subsequent cereal crops. There was no evidence during the ley fertility building phase that red clover monoculture (RC) had a strong positive effect on grass productivity when in mixtures, irrespective of the cutting system. In cut/mulch, the red clover/ryegrass/cocksfoot (RCRGCF) mixture had least dry matter and N yields of all red clover-based leys. In the arable phase, all red clover-based leys gave subsequent winter wheat grain yields comparable to those of best conventional management. The cutting system had an effect only on red clover/ryegrass (RCRG) and ryegrass (RG). Maximum grain yield of winter wheat occurred after mulching of RCRG. For spring wheat, the preceding sown species or the cutting system had no effect on grain yield, partly due to preceding wet weather. RC consistently had greater grain protein in both subsequent winter and spring wheat. Growing short-term RC as a fertility-building forage crop could significantly improve grain protein content in both winter and spring wheat, regardless of management. RC could potentially be of economic importance, especially in low input stockless farming, where N supplementation may be limited.

Achieving successful farmer engagement on greenhouse gas emission mitigation

This paper explores the potential for farmers’ engagement on the issues related to greenhouse gas (GHG) emission mitigation in extensive low-input livestock farming systems. The framework used was based on Participatory Action Research. This involved integrating quantitative evidence on GHG emission impacts at the farm level and qualitative data on the obstacles to the adoption of innovation based on farmers’ perceptions and attitudes to climate change. The study aims at building social capital among 14 farmers in the South West and West Midlands regions in England, and it evaluates the potential for the adoption of emission mitigation strategies. The Rapid Farm Practices Appraisal (RFPA) tool was created to assess farm practices based on their mitigation potential. Practices were assessed twice over 6–9 months. Semi-structured interviews were used to assess barriers and opportunities to farmer engagement and on-farm innovation. Farmers were invited to a focus group meeting to network with other farmers and engage with researchers. All farmers participated in the 2 farm assessments, but only half the farmers adopted changes in farm management. All farmers appreciated the RFPA tool, the clearness of the information provided and the focus of the tool on practices directly. The main obstacles to innovation were limited financial capital, lack of trust in government action and confusion over the effectiveness of farm advice on mitigation. The lack of long-term flexibility of agricultural policies and the source of information greatly influenced the acceptance of advice. Results suggest the potential for the expansion of the RFPA tool to include economic assessment of farm practices and the engagement of a larger pool of farmers and farming systems. The tool could be used to support the GHG Action Plan and future environmental policies, and as an integrated self-assessment tool for farmers under Environmental Stewardship Schemes.

Influences of two-year red clover-grass ley management on nitrogen economy and following wheat performance

A two-year ley field experiment was established in May 2009 with six combinations of red clover, perennial ryegrass and cocksfoot, and two fallow control plots, to determine the impact of ‘cut and remove’ of the crops three times or ‘cut and mulch’ once annually on biomass yield, nitrogen (N) accumulation, soil mineralization and subsequent cereal performance. Farmyard manure was added to one of the fallow treatments at the beginning of the arable phase. The experiment was conducted on a clay loam soil at Moreton-in-Marsh, Gloucestershire, UK (NGR SP 217 323). During the ley fertility-building phase, there was no evidence that red clover (RC) had a synergistic effect on grass productivity when in mixtures, irrespective of cutting system. Accumulated above ground N over the 2 years was greater in cut/removed red clover-based leys (330–365 kg ha− 1) grass and fallow plots. In cut/mulched leys, RC was higher (113 kg ha− 1) than the rest. Soil potential mineralizable N (PMN) was not related to ley N yields but was consistently high in the red clover/ryegrass/cocksfoot (RCRGCF) treatments during winter and spring wheat. There was no indication that wheat yields and quality were improved following any red clover combinations or cutting regimes. These results suggest mixing RC with two grasses, RG and CF are likely to improve soil mineralization potential. Nevertheless, growing red clover leys over 2 years and mulching once annually under variable weather could limit soil N accumulation. In such conditions, growing red clover leys for a shorter period and removing herbage may be a better option.

Organic wheat performance following conventional and non-inversion tillage systems

Field trials were conducted from October 2010 to August 2012 on land registered with the Soil Association, UK, for organic production on the Royal Agricultural Universitys Harnhill Manor Farm near Cirencester, UK, to compare the effects of conventional tillage (CT) involving maximum soil manipulation and 0% soil surface plant residues against conservation tillage strategy including low residue non-inversion tillage (LRNiT) involving minimal soil movements and 30% soil surface plant residues and also high residue non-inversion tillage (HRNiT) with least soil movements and maximum (>50%) retention of soil surface plant residues on organic winter and spring wheat performance. Establishment, growth and the yield response of organic winter and spring wheat for the three cultivation systems were assessed to determine the influence of these tillage treatments. Results showed that the plant establishment and tillers were significantly higher in CT than LRNiT and HRNiT in both cropping seasons. The total number of shoots, ear numbers, dry matter yield, 1000 grain weights and grain yield were significantly higher in the CT and LRNiT than HRNiT for winter wheat, whilst they were significantly higher in the CT than LRNiT or HRNiT for spring wheat. Crop establishment, growth and yield response were influenced by the weather conditions beyond the tillage treatments for the spring wheat compared with the winter wheat. On the basis of these results, a better alternative for CT could be LRNiT for winter wheat. Conversely, for spring wheat, CT had better crop establishment, growth and yield than other forms of cultivation.

Weed manifestation under different tillage and legume undersowing in organic wheat

Field experiments from October 2010 to August 2012 were conducted at the Royal Agricultural Universitys organic Harnhill Manor Farm near Cirencester, UK to explore tillage and legume undersowing effects on dry matter (DM) of broadleaf and grass weed infestation in organic winter and spring wheat. The experiments were designed using a randomized complete block with split plot arrangements. Tillage treatments involved conventional tillage (CT), low residue non-inversion tillage (LRNiT) and high residue non-inversion tillage (HRNiT) as main plots with undersowing white clover (WC), black medic (BM) or non-undersown (Nus) as subplots. In both cropping seasons, among tillage treatments, HRNiT had significantly higher total weed DM than CT or LRNiT. The mid-season assessments for weed species indicated HRNiT as having significantly higher grass weed DM than CT or LRNiT for both the wheat types. Broadleaf weed DM was significantly higher under CT than under LRNiT or HRNiT for winter wheat after GS61, whereas for spring wheat, broadleaf weed DM was significantly higher under CT than under HRNiT throughout the growing season. Undersowing had a significant effect only in spring wheat. Among undersowing treatments, WC had significantly lower total weed DM than BM. The broadleaf weed DM was significantly lower under WC than under BM or Nus. On the basis of these results, increasing the levels of tillage intensity with complete (0%) or minimal (30%) dispersion of soil cover appears to have decreased grass weed and total weed DM. Among undersowing treatments, WC seems to be a more reliable option than BM for spring wheat.

Red clover (Trifolium pratense) in conservation agriculture: a compelling case for increased adoption

ABSTRACT The rapidly growing population will soon require a near doubling of food production. This increase must be achieved in a manner that maintains environmental integrity, preserves public health and resolves food access and distribution equalities. The use of forage legumes in arable rotations can make significant and multidimensional contributions to this sustainable intensification and this paper reviews the potential contribution of red clover (Trifolium pratense L.), with particular reference to sustainable cereal production in conservation agriculture systems. The use of red clover as a tool in soil fertility-building and the multiple benefits to the cropping system in which it is used is described. The benefits discussed include atmospheric nitrogen fixation, soil conservation, structural soil improvements and a suite of agroecosystem services including increased soil microbial activity, the phytoremediation of polluted soils and the provision of food for pollinators. Reported allelopathic weed suppression by red clover cover crops and the role of modern plant breeding in creating new varieties that further enhance system sustainability is also discussed. Finally, as economic considerations will always impact on adoption rates, the profitability of red clover rotations in terms of silage value and yield benefits is taken into account.

Soil mineral nitrogen availability predicted by herbage yield and disease resistance in red clover (Trifolium pratense) cropping

Nitrogen (N) is the most limiting nutrient in crop production. Legumes such as red clover can provide N through biofixation, but securing nitrogen in soil for subsequent crop production must also be considered. Variety selection and management in red clover cropping can influence soil mineral nitrogen (SMN) availability. A field trial to investigate this was conducted with six varieties, under one and two cut management, over 2xa0years. Dry matter (DM) and N yield, Sclerotinia resistance and SMN availability were assessed. Low DM and N yields (1.6–2.4xa0txa0DMxa0ha−1 and 54–83xa0kgxa0Nxa0ha−1) in the first year of cultivation allowed ~u200940xa0kgxa0Nxa0ha−1 to become available, but high DM and N yields (10.2–14.6xa0txa0DMxa0ha−1 and 405–544xa0kgxa0Nxa0ha−1) allowed ~u200920xa0kgxa0Nxa0ha−1 to become available. Wetter weather in 2015 caused significantly more SMN losses than 2016 (20xa0kgxa0Nxa0ha−1 in 2015 and 5xa0kgxa0Nxa0ha−1 in 2016). The varieties Amos, Maro and Milvus lost significantly more SMN in the winter period, which may have been caused by more severe infection of Sclerotinia (these varieties were 50–80% more severely infected other varieties). Varietal effect was non-significant for winter losses in 2016, where no significantxa0varietal differences in Sclerotinia infection were observed. 1 cut made ~u200941xa0kgxa0Nxa0ha−1 available in the growing season of 2015, whilst 2 cut made significantly less (37xa0kgxa0Nxa0ha−1). Cutting was non-significant in 2016 but 1 cut was less susceptible to losses in the winter period. Cutting in 2015 did not significantly affect herbage DM and N yields in the first or second cut of 2016.